Different machine tools are used in machining, such as milling machines, horizontal boring and milling machines and drilling machines. Lathes may also comprise rotating tools. Machine tools comprise a spindle, in which a tool can be arranged, which can be made to rotate around its axis by rotating the spindle. The tool comprises a body having fastening means for fastening the tool to the spindle. The tool further comprises at least one cutting part having a cutting edge for detaching material from an object being machined. The cutting part typically comprises an insert, which can be replaced when required. The cutting part may comprise an insert holder for fastening the insert. Conventionally, the cutting part is preset by moving the insert holder relative to the body of the tool into an accurately predetermined position, after which it is locked immobile. The insert holder usually comprises a mechanical locking, usually a screw locking, for holding the cutting part in the set position. Consequently, such a tool has only one fixed measure that can no longer be changed in the machine tool. For example, a special boring tool has to exist for each hole to be bored and having a different diameter. The problem herein is that the number of tools becomes large. However, there is not always sufficient space in the tool magazines of machine tools for all different tools, not to mention reserve tools. This presents a significant drawback particularly in automatic machine tools intended for unmanned drive. Furthermore, much time is taken by change of tools when machining with a tool having a special form, since a special tool, set to one measure, has to be retrieved for each measure machined, which naturally impairs the performance of machining.
As a solution to the above problem, a tool for machining has been developed, wherein the cutting part can be moved relative to the body of the tool by means of an electric actuator. However, one of the drawbacks is that the electric conductor has to be led to the rotating tool through the spindle. In addition, the machine tool has to comprise a special separate control apparatus for controlling the actuator. Consequently, an electrically controlled tool is subject to significant changes in conventional machine tools. Furthermore, an electrically controlled tool is susceptible to malfunction under demanding machine shop circumstances. A further drawback of an electrically adjustable tool is its high price.